1 files changed, 117 insertions, 0 deletions
diff --git a/drivers/iio/dummy/iio_simple_dummy_buffer.c b/drivers/iio/dummy/iio_simple_dummy_buffer.c
new file mode 100644
index 000000000000..e35e0596cbfb
--- /dev/null
+++ b/drivers/iio/dummy/iio_simple_dummy_buffer.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2011 Jonathan Cameron
+ *
+ * Buffer handling elements of industrial I/O reference driver.
+ * Uses the kfifo buffer.
+ *
+ * To test without hardware use the sysfs trigger.
+ */
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/bitmap.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#include "iio_simple_dummy.h"
+
+/* Some fake data */
+
+static const s16 fakedata[] = {
+	[DUMMY_INDEX_VOLTAGE_0] = 7,
+	[DUMMY_INDEX_DIFFVOLTAGE_1M2] = -33,
+	[DUMMY_INDEX_DIFFVOLTAGE_3M4] = -2,
+	[DUMMY_INDEX_ACCELX] = 344,
+};
+
+struct dummy_scan {
+	s16 data[ARRAY_SIZE(fakedata)];
+	aligned_s64 timestamp;
+};
+
+/**
+ * iio_simple_dummy_trigger_h() - the trigger handler function
+ * @irq: the interrupt number
+ * @p: private data - always a pointer to the poll func.
+ *
+ * This is the guts of buffered capture. On a trigger event occurring,
+ * if the pollfunc is attached then this handler is called as a threaded
+ * interrupt (and hence may sleep). It is responsible for grabbing data
+ * from the device and pushing it into the associated buffer.
+ */
+static irqreturn_t iio_simple_dummy_trigger_h(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct dummy_scan *scan;
+	int i = 0, j;
+
+	/*
+	 * Note that some buses such as SPI require DMA safe buffers which
+	 * cannot be on the stack. Two easy ways to do this:
+	 *  - Local kzalloc (as done here)
+	 *  - A buffer at the end of the structure accessed via iio_priv()
+	 *    that is marked __aligned(IIO_DMA_MINALIGN).
+	 */
+	scan = kzalloc(sizeof(*scan), GFP_KERNEL);
+	if (!scan)
+		goto done;
+
+	/*
+	 * Three common options here:
+	 * hardware scans:
+	 *   certain combinations of channels make up a fast read. The capture
+	 *   will consist of all of them. Hence we just call the grab data
+	 *   function and fill the buffer without processing.
+	 * software scans:
+	 *   can be considered to be random access so efficient reading is just
+	 *   a case of minimal bus transactions.
+	 * software culled hardware scans:
+	 *   occasionally a driver may process the nearest hardware scan to avoid
+	 *   storing elements that are not desired. This is the fiddliest option
+	 *   by far.
+	 * Here let's pretend we have random access. And the values are in the
+	 * constant table fakedata.
+	 */
+	iio_for_each_active_channel(indio_dev, j)
+		scan->data[i++] = fakedata[j];
+
+	iio_push_to_buffers_with_ts(indio_dev, scan, sizeof(*scan),
+				    iio_get_time_ns(indio_dev));
+
+	kfree(scan);
+done:
+	/*
+	 * Tell the core we are done with this trigger and ready for the
+	 * next one.
+	 */
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static const struct iio_buffer_setup_ops iio_simple_dummy_buffer_setup_ops = {
+};
+
+int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev)
+{
+	return iio_triggered_buffer_setup(indio_dev, NULL,
+					  iio_simple_dummy_trigger_h,
+					  &iio_simple_dummy_buffer_setup_ops);
+}
+
+/**
+ * iio_simple_dummy_unconfigure_buffer() - release buffer resources
+ * @indio_dev: device instance state
+ */
+void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev)
+{
+	iio_triggered_buffer_cleanup(indio_dev);
+}